Method of random access in a wireless system

ABSTRACT

A random access method in a wireless communication system is disclosed. The present invention includes transmitting a bandwidth request indicator and a quick access message from a mobile station to a base station and starting a timer having a timer value determined according to an acknowledgement from the base station.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser.Nos. 61/167,161, filed on Apr. 7, 2009, 61/168,203, filed on Apr. 9,2009, 61/175,060, filed on May 4, 2009, 61/149,343, filed on Feb. 3,2009, 61/145,933, filed on Jan. 20, 2009, 61/167,834, filed on Apr. 8,2009, and 61/144,193, filed on Jan. 13, 2009, the contents of which arehereby incorporated by reference herein in their entirety. Pursuant to35 U.S.C. §119(a), this application claims the benefit of earlier filingdate and right of priority to Korean Patent Application Nos.10-2008-0087291, filed on Sep. 4, 2008, 10-2008-0093746, filed on Sep.24, 2008, 10-2009-0022525, filed on Mar. 17, 2009, 10-2009-0028669,filed on Apr. 2, 2009, 10-2009-0060583, filed on Jul. 3, 2009, and10-2009-0067794, filed on Jul. 24, 2009, the contents of which arehereby incorporated by reference herein in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a wireless system, and moreparticularly, to a method of random access in a wireless communicationsystem.

2. Discussion of the Related Art

First of all, a random access method in a wireless communication systemaccording to a related art is explained with reference to FIG. 1 asfollows. FIG. 1 is a diagram for a random aces method in wirelesscommunication system according to a related art.

Referring to FIG. 1, a mobile station selects one of ranging codes froma bandwidth request code (BR code) set to request an uplink bandwidthand then transmits the selected one to a base station [S110]. The mobilestation starts a timer after having transmitted the bandwidth requestcode to the base station. In this case, the timer is a contention-basedreservation timeout or a T3.

Having normally received the code transmitted by the mobile station, thebase station allocates an uplink resource for sending a bandwidthrequest (BW-REQ) message to the mobile station [S120]. If the mobilestation fails to have the uplink resource allocated thereto until thetimer ends after transmission of the bandwidth code, it retransmits thebandwidth code.

The mobile station sends a bandwidth request message via the allocatedregion [S130]. Having received the bandwidth request message transmittedfrom the mobile station, the base station allocates an uplink resourceto the mobile station [S140]. Subsequently, the mobile station transmitsdata to the base station via the allocated uplink resource [S150].

In the following description, a random aces method in a future broadbandwireless access system is explained with reference to FIG. 2. FIG. 2 isa diagram for a random access method in a future broadband wirelessaccess system. First of all, in a future broadband wireless accesssystem, a base station simultaneously supports a general 5-step schemeand a 3-step scheme (quick access scheme) both. The 5-step scheme isusable in a manner of being independent from the 3-step scheme or can beused in a 3-step fallback mode.

According to the 3-step scheme, referring to FIG. 2, a mobile stationsends a quick access message including a bandwidth request indicatorselected randomly or by a predetermined rule and uplink bandwidthrequest information to a base station [S210]. In this case, thebandwidth request indicator can be a bandwidth request (BR) sequence ora bandwidth request code. And, the uplink bandwidth request informationcan include a mobile station ID (station ID), a bandwidth request sizeand the like.

The base station transmits ACK/NACK (acknowledgement/negativeacknowledgement) in response to the bandwidth request indicator to themobile station [S220]. Having normally received the bandwidth requestindicator and the quick access message, the base station allocates anuplink resource for data transmission to the mobile station [S260]. Themobile station then transmits data to the base station via the allocatedresource [S270]. In doing so, the mobile station is able to transmitadditional uplink bandwidth request information to the base station.

According to the 5-step scheme, if a mobile station transmits a randomlyselected bandwidth request indicator to a base station [S210], the basestation transmits ACK/NACK to the mobile station in response to thebandwidth request indicator from the mobile station [S220]. The basestation allocates an uplink resource for a bandwidth request messagetransmission to the mobile station via CDMA Allocation A-MAP IE(advanced MAP information element) [S230].

The mobile station sends a bandwidth request message to the base stationvia the allocated region [S240]. If so, the base station transmitsACK/NACK to the mobile station in response to the bandwidth requestmessage [S250]. The base station allocates an uplink resource to themobile station via an uplink basic assignment A-MAP IE (UL basicassignment A-MAP IE) [S260]. The mobile station then transmits data tothe base station via the allocated region [S270]. In doing so, themobile station is able to transmit additional uplink bandwidth requestinformation to the base station.

FIG. 3 is a diagram of a ranging process in a wireless communicationsystem according to a related art.

Referring to FIG. 3, in order to perform initial ranging, a mobilestation selects one of ranging codes from an initial ranging code setand then transmits the selected ranging code to a base station [S310].Having normally received the ranging code from the mobile station, thebase station allocates an uplink resource for transmitting a rangingrequest message (Ranging-REQ message) to the mobile station [S320].According to a temporal status of the ranging code, the base station isable to send a ranging response message (Ranging-RSP message) to themobile station. If the mobile station fails to receive the uplinkresource or the ranging response message until the end of a timer (acontent-based reservation timeout or T3), which started aftertransmission of the ranging code, the mobile station retransmits theranging code.

The mobile station, to which the uplink resource for sending a rangingrequest message has bee allocated, sends the ranging request message viathe allocated region [S330]. If so, the base station sends a rangingresponse message to the mobile station [S340]. In this case, the rangingincludes handover ranging and periodic ranging as well as the initialranging.

In the following description, explained are a process for requesting anuplink bandwidth by random access in a future broadband wireless accesssystem and a process for performing a ranging in a future broadbandwireless access system.

FIG. 4 is a diagram of a process for requesting an uplink bandwidth in afuture broadband wireless access system.

First of all, in a future broadband wireless access system, a basestation simultaneously supports a bandwidth request process of a general5-step scheme and a bandwidth request process of a 3-step scheme (quickaccess scheme) both. The 5-step scheme is usable in a manner of beingindependent from the 3-step scheme or can be used in a 3-step fallbackmode.

According to the 3-step scheme, referring to FIG. 4, a mobile stationsends a quick access message including a bandwidth request indicatorselected randomly or by a predetermined rule and uplink bandwidthrequest information to a base station [S410]. In this case, thebandwidth request indicator can be a bandwidth request (BR) sequence ora bandwidth request code. And, the uplink bandwidth request informationcan include a mobile station ID (station ID), a bandwidth request sizeand the like.

The base station transmits ACK/NACK (acknowledgement/negativeacknowledgement) in response to the bandwidth request indicator to themobile station [S420]. Having normally received the bandwidth requestindicator and the quick access message, the base station allocates anuplink resource for data transmission to the mobile station [S460]. Themobile station then transmits data to the base station via the allocatedresource [S470]. In doing so, the mobile station is able to transmitadditional uplink bandwidth request information to the base station.

According to the 5-step scheme, if a mobile station transmits a randomlyselected bandwidth request indicator to a base station [S410], the basestation transmits ACK/NACK to the mobile station in response to thebandwidth request indicator from the mobile station [S420]. The basestation allocates an uplink resource for a bandwidth request messagetransmission to the mobile station via CDMA Allocation A-MAP IE(advanced MAP information element) [S430].

The mobile station sends a bandwidth request message to the base stationvia the allocated region [S440]. If so, the base station then allocatesan uplink resource to the mobile station via an uplink basic assignmentA-MAP IE (UL basic assignment A-MAP IE) [S460]. The mobile station thentransmits data to the base station via the allocated region [S470]. Indoing so, the mobile station is able to transmit additional uplinkbandwidth request information to the base station.

FIG. 5 is a diagram of a process for performing a ranging in a futurebroadband wireless access system.

Referring to FIG. 5, if a mobile station transmits a ranging indicatorto a base station [S510], the base station transmits ACK/NACK to themobile station in response to the ranging indicator [S520] and allocatesan uplink resource for a ranging request message transmission to themobile station [S530]. If so, the mobile station sends a ranging requestmessage to the base station [S540]. The base station then sends aranging response message to the mobile station [S550].

As mentioned in the above description, in a broadband wireless accesssystem, a base station receives such a random access code as a bandwidthrequest indicator and a ranging indicator from a mobile station and thentransmits a corresponding ACK/NACK to the mobile station. Therefore, amethod of minimizing an overhead of the ACK/NACK is necessary.

SUMMARY OF THE INVENTION

However, as mentioned in the foregoing description, in the related art,a same resource allocation standby type is applied to all mobilestations. And, a same resource allocation standby time is applied to alldata transmitted by one mobile station. Therefore, the related art has aproblem that a proper resource allocation standby time is not setaccording to QoS (quality of service). Moreover, a method of minimizingan overhead of ACK/NACK for a random access code of a mobile station ina broadband wireless access system is necessary. Since a base station isable to transmit ACK/NACK for a quick access message or a bandwidthrequest message to a mobile station, the mobile station is able to raiseefficiency of a wireless system if a random access scheme variesaccording to the ACK/NACK.

Accordingly, the present invention is directed to a method of randomaccess in a wireless communication system that substantially obviatesone or more of the problems due to limitations and disadvantages of therelated art.

An object of the present invention is to provide a method oftransmitting a bandwidth request using a proper resource allocationstandby time according to QoS.

Another object of the present invention is to provide method oftransmitting a bandwidth request using a proper resource allocationstandby time in consideration of a priority of a mobile station.

Another object of the present invention is to provide method oftransmitting and receiving ACK/NACK, by which an overhead of ACK/NACKfor a random access code of a mobile station can be minimized.

A further object of the present invention is to provide method of randomaccess according to ACK/NACK of a base station in response to abandwidth request indicator, quick access message or bandwidth requestmessage transmitted by a mobile station.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. Theobjectives and other advantages of the invention will be realized andattained by the structure particularly pointed out in the writtendescription and claims thereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described, a randomaccess method of a mobile station in a wireless communication systemaccording to one embodiment of the present invention includes the stepsof transmitting a bandwidth request indicator and a quick access messageto a base station and starting a timer having a timer value determinedaccording to an acknowledgement from the base station.

Preferably, in the timer starting step, if the acknowledgementindicating that the base station does not receive the bandwidth requestindicator or the quick access message is not received from the basestation, the mobile station starts the timer having a differentiatedvalue determined according to a characteristic of data to transmit.

More preferably, the mobile station is able to stop the timer if anuplink resource is allocated by the base station.

More preferably, if an uplink resource is not allocated to the mobilestation by the base station until the timer expires, the mobile stationis able to retransmit the bandwidth request indicator and the quickaccess message to the base station.

Preferably, in the timer starting step, if the acknowledgementindicating that the base station succeeds in decoding of the bandwidthrequest indicator but fails in decoding of the quick access message isreceived from the base station, it is able to start the timer having adefault value previously determined between the base station and themobile station.

More preferably, if an uplink resource is allocated by the base station,the mobile station stops the timer and transmits a bandwidth requestmessage to the base station via the uplink resource. If theacknowledgement indicating that the base station fails to receive thebandwidth request message is not received from the base station, themobile station is able to start the timer having a differentiated valuedetermined according to a characteristic of data to be transmitted bythe mobile station.

In this case, if the uplink resource is not allocated by the basestation until the timer having the differentiated value expires, themobile station is able to retransmit the bandwidth request indicator orthe bandwidth request message to the base station.

To further achieve these and other advantages and in accordance with thepurpose of the present invention, a random access method of a mobilestation in a wireless communication system according to anotherembodiment of the present invention includes the steps of transmitting abandwidth request indicator to a base station and if an acknowledgementindicating that the base station fails to receive the bandwidth requestindicator is not received from the base station, starting a timer havinga default value previously determined between the base station and themobile station.

To further achieve these and other advantages and in accordance with thepurpose of the present invention, in a mobile station of a wirelesscommunication system, a method of performing a bandwidth requestprocedure using a random access according to another embodiment of thepresent invention includes the steps of transmitting a first bandwidthrequest to a base station to request a resource allocation for a datatransmission and if there is no response from the base station for aresource allocation standby time determined variably, transmitting asecond bandwidth request to the base station.

Preferably, the first resource allocation standby time can be determinedaccording to a QoS level of the data or a priority of the mobilestation.

Preferably, the resource allocation standby time can include a resourceallocation standby time corresponding to the QoS level of the data inthe per-QoS level resource allocation standby time received via abroadcast message or a MAC message.

Preferably, the mobile station receives a per-index resource allocationstandby time from the base station via a broadcast message and an indexof the resource allocation standby time determined in consideration ofthe QoS level in the per-index resource allocation standby time bytransmitting a MAC message including information on the QoS level of thedata to the base station. Therefore, the mobile station is able to use aresource allocation standby time corresponding to the received index asthe resource allocation standby time.

Preferably, the mobile station transmits a MAC message includinginformation on the QoS level of the data to the base station and is thenable to receive a MAC message including the first resource allocationstandby time determined in consideration of the QoS level from the basestation.

To further achieve these and other advantages and in accordance with thepurpose of the present invention, in a mobile station of a wirelesscommunication system, a method of receiving an acknowledgement(hereinafter abbreviated ACK) according to another embodiment of thepresent invention includes the steps of transmitting a random accesscode to a base station via a first resource region and receiving the ACKfrom the base station via a second resource region temporally spacedapart from the first resource region by an ACK delay.

To further achieve these and other advantages and in accordance with thepurpose of the present invention, in a base station of a wirelesscommunication system, a method of transmitting an acknowledgement(hereinafter abbreviated ACK) according to another embodiment of thepresent invention includes the steps of receiving a random access codefrom a mobile station via a first resource region and transmitting theACK to the mobile station via a second resource region temporally spacedapart from the first resource region by an ACK delay.

Preferably, the first resource region is a transmission opportunityincluding at least one resource unit. And, the transmission opportunitycan be assigned to a radio resource by a subframe or frame unit.

Preferably, the ACK delay can be defined by a subframe unit.

Preferably, the ACK delay is defined by a frame unit and the secondresource region belongs to a frame spaced apart from a frame having thefirst resource region belong thereto by the ACK delay.

More preferably, the second resource region can belong to a subframedetermined according to a subframe having the first resource regionbelong thereto within the frame spaced apart from the frame having thefirst resource region belong thereto.

Preferably, a value of the ACK delay can be transmitted from the basestation to the mobile station.

Preferably, a value of the ACK delay can be determined between themobile station and the base station in advance.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

In the drawings:

FIG. 1 is a diagram for a random aces method in wireless communicationsystem according to a related art;

FIG. 2 is a diagram for a random access method in a future broadbandwireless access system;

FIG. 3 is a diagram of a ranging process in a wireless communicationsystem according to a related art;

FIG. 4 is a diagram of a process for requesting an uplink bandwidth in afuture broadband wireless access system;

FIG. 5 is a diagram of a process for performing a ranging in a futurebroadband wireless access system;

FIG. 6 is a diagram of a process for allocating a resource in a wirelesscommunication system according to an embodiment of the presentinvention;

FIG. 7 is a diagram for a method of performing a bandwidth requestprocess in a wireless communication system according to a firstembodiment of the present invention in a 3-step scheme;

FIG. 8 is a diagram for a case of setting a response information standbytime for a BW-REQ message to be equal to a resource allocation standbytime in a 5-step scheme;

FIG. 9 is a diagram for a case of setting a response information standbytime for a BW-REQ message to be different from a resource allocationstandby time in a 5-step scheme;

FIG. 10 is a diagram for a method of performing a bandwidth requestprocess in a wireless communication system according to a secondembodiment of the present invention in a 3-step scheme;

FIG. 11 is a diagram for a case of using a DSA-RSP message in a methodof performing a bandwidth request process in a wireless communicationsystem according to a third embodiment of the present invention;

FIG. 12 is a diagram for a case of using a DNG-RSP message in a methodof performing a bandwidth request process in a wireless communicationsystem according to a third embodiment of the present invention;

FIG. 13 is a diagram for a method of performing a bandwidth requestprocess using one resource allocation standby time applicable to allconnections of one mobile station;

FIG. 14 is a diagram for a method of performing a bandwidth requestprocess using a resource allocation standby time differing according toa QoS level for a plurality of connections of one mobile station;

FIG. 15 is a diagram for a method of performing a bandwidth requestprocess in a wireless communication system according to a fourthembodiment of the present invention;

FIG. 16 is a flowchart of a process for resource allocation in a basestation;

FIG. 17 is a diagram for a case of setting a timer after a mobilestation has received response information in response to a bandwidthrequest indicator;

FIG. 18 is a diagram for a case of setting a timer after a mobilestation has received response information in response to a bandwidthrequest indicator.

FIG. 19 is a diagram for a data format of a difference value if aresource allocation standby time is transmitted in form of thedifference value from a default value.

FIG. 20 is a flowchart for a method of receiving ACK/NACK in a wirelesscommunication system according to an embodiment of the presentinvention;

FIG. 21( a) is a diagram of a transmission opportunity set if atransmission opportunity is allocated by a subframe unit;

FIG. 21( b) is a diagram of a transmission opportunity set if atransmission opportunity is allocated by a frame unit;

FIG. 22( a) is a diagram for an ACK transmission timing point if atransmission opportunity is assigned by a subframe unit and an ACK delayis defined by a subframe unit, when a ratio of a downlink versus anuplink is 5:3;

FIG. 22( b) is a diagram for an ACK transmission timing point if atransmission opportunity is assigned by a subframe unit and an ACK delayis defined by a subframe unit, when a ratio of a downlink versus anuplink is 4:4;

FIG. 23( a) is a diagram for an ACK transmission timing point if atransmission opportunity is assigned by a subframe unit and an ACK delayis defined by a frame unit, when a ratio of a downlink versus an uplinkis 5:3;

FIG. 23( b) is a diagram for an ACK transmission timing point if atransmission opportunity is assigned by a subframe unit and an ACK delayis defined by a frame unit, when a ratio of a downlink versus an uplinkis 4:4;

FIG. 24 is a diagram for an ACK transmission timing point if atransmission opportunity is assigned by a frame unit and an ACK delay isdefined by a subframe unit, when a ratio of a downlink versus an uplinkis 4:4;

FIG. 25 is a diagram for an ACK transmission timing point if atransmission opportunity is assigned by a frame unit and an ACK delay isdefined by a frame unit, when a ratio of a downlink versus an uplink is4:4;

FIG. 26 is a diagram for a case that a base station informs a mobilestation whether ACK is supported by broadcast;

FIG. 27 is a diagram for a case that a base station informs a mobilestation whether ACK is supported by unicast;

FIG. 28 is a diagram of a process for a mobile station to transmit abandwidth request indicator according to a first embodiment of thepresent invention;

FIG. 29 is a diagram of a process for a mobile station to stand by foran uplink resource allocation according to a first embodiment of thepresent invention;

FIG. 30 is a diagram of a process for receiving a bandwidth requestindicator in a base station according to a first embodiment of thepresent invention;

FIG. 31 is a diagram of a process for a base station to re-obtainwhether a resource for allocation exists according to a first embodimentof the present invention;

FIG. 32 is a diagram for a base station to receive a bandwidth requestmessage according to a first embodiment of the present invention; and

FIG. 33 is a diagram for a case that a mobile station retransmits abandwidth request indicator.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings, to facilitate those having ordinary skill in the art toimplement the invention. The present invention can be implemented invarious forms, which is non-limited by the following embodiments. Toclearly describe the present invention, parts irrespective of thedescription are omitted from the drawings. Wherever possible, the samereference numbers will be used throughout the drawings to refer to thesame or like parts.

Throughout this disclosure, if a prescribed part ‘includes’ a prescribedelement, it means that another element can be further included insteadof eliminating other elements as long as absence of special objection.Moreover, such a terminology as ‘part’ ‘unit’, ‘module’ and the likemeans a unit for handling at least one function or operation, which canbe implemented by software, hardware or combination thereof.

First of all, a process for allocating a resource in a wirelesscommunication system according to an embodiment of the present inventionis explained with reference to FIG. 6.

FIG. 6 is a diagram of a process for allocating a resource in a wirelesscommunication system according to an embodiment of the presentinvention.

In a wireless communication according to the present invention, a basestation supports a 5-step scheme and a 3-step scheme (quick accessscheme) both. By the 3-step scheme, steps 5610, 5640 and 5650 shown inFIG. 6 are performed. By the 5-step scheme, all steps 5610 to 5650 areperformed. The 5-step scheme is usable by being independent from the3-step or can be used as a substitute for the 3-step scheme.

Referring to FIG. 6, in the 3-step scheme, a mobile station transmits abandwidth request for requesting a resource allocation for a datatransmission to a base station. In this case, the bandwidth request isthe information first transmitted by the mobile station to make arequest for the resource allocation to the base station. And, thebandwidth request can be carried on an indicator or both indicator andmessage (quick access message). The bandwidth request includesinformation on a necessary uplink resource and can include a mobilestation ID (MS ID), a bandwidth request size and a QoS level.

The QoS level means a level of QoS requested by the mobile station andcan be replaced by such a terminology as a QoS index, a QoS ID and thelike. The QoS level can be determined according to various QoSparameters including a grant scheduling type, a latency and the like.

In this embodiment of the present invention, a bandwidth request iscarried on a bandwidth request indicator for example, by which thepresent invention is non-limited. And, this embodiment includes a caseof transmitting a code, a random access preamble, a message or the liketo request a bandwidth from a base station.

Having received the bandwidth request indicator from the mobile station,the base station allocates an uplink resource to the mobile station[S640]. The mobile station then transmits data via the allocatedresource [S650]. In doing so, the mobile station is able to transmitadditional uplink bandwidth request information.

In the 5-step scheme, if the mobile station transmits the bandwidthrequest indicator to the base station [S610], the base station allocatesan uplink resource for sending a bandwidth request message (BW-REQmessage) to the mobile station [S620]. If the mobile station sends abandwidth request message via the allocated resource [S630], the basestation allocates an uplink resource to the mobile station [S640]. Themobile station then transmits data via the allocated resource [S650]. Indoing so, the mobile station is able to transmit additional uplinkbandwidth request information.

According to one embodiment of the present invention, in transmitting abandwidth request indicator or a bandwidth request message, a mobilestation is able to transmit a QoS level of data to transmit togetherwith a mobile station ID and a bandwidth request size. A base station isable to grant a priority to a bandwidth request made by each mobilestation and is able to recognize a resource allocation standby timewhich is to be used by the mobile station.

According to another embodiment of the present invention, intransmitting a bandwidth request indicator or a bandwidth requestmessage, a mobile station is able to transmit an index of a resourceallocation standby time to be used together with a mobile station ID anda bandwidth request size.

According to a further embodiment of the present invention, intransmitting a bandwidth request indicator or a bandwidth requestmessage, a mobile station is able to transmit a flow identification (ID)together with a mobile station ID and a bandwidth request size. A basestation is then able to estimate a QoS level of data, which is to betransmitted by the mobile station, or an index of a resource allocationstandby time which is to be used by the mobile station.

The base station is able to estimate a timing point of transmitting abandwidth request indicator or a bandwidth request message, a QoS levelof data which is to be transmitted by the mobile station via a resourceregion for transmitting a bandwidth request indicator or a bandwidthrequest message or information of a bandwidth request code, or an indexof a resource allocation standby time which is to be used by the mobilestation.

If prescribed information delivered via a message (quick access message)transmitted together with a bandwidth request indicator or a bandwidthrequest message (BW-REQ message) includes QoS information, the basestation is able to estimate a QoS level of data to be transmitted by themobile station or an index of a resource allocation standby time to beused by the mobile station using the QoS information. For instance, if abandwidth request size includes characteristics (e.g., a presence ornon-presence of signaling data, a service type, urgency for a request)of the request as well as information on a size, it is able to estimatean index of a resource allocation standby time through this information.

In case that a mobile station makes a request for a plurality ofconnections via one bandwidth request indicator or one bandwidth requestmessage to a base station, the mobile station transmits a QoS level othe connection having a highest QoS level of data to transmit among aplurality of the connections or an index of a resource allocationstandby time of the connection having a smallest resource allocationstandby time to use.

If a mobile station does not transmit a QoS level, an index of aresource allocation standby time, or a value for estimating the QoSlevel or the index of the resource allocation standby time, the mobilestation and the base station is able to apply a predetermined timervalue by a superframe header (hereinafter abbreviated SFH), a messagebased explicit scheme or a message based implicit scheme.

In the following description, a bandwidth request transmitting method ina wireless communication system according to an embodiment of thepresent invention is explained with reference to FIGS. 7 to 11.

According to an embodiment of the present invention, a mobile stationtransmits a bandwidth request to a base station to make a request for aresource allocation for a data transmission and then stands by for aresource allocation standby time determined according to a QoS level ofdata to transmit.

FIG. 7 is a diagram for a method of performing a bandwidth requestprocess in a wireless communication system according to a firstembodiment of the present invention in a 3-step scheme. According to afirst embodiment of the present invention, a base station transmits aresource allocation standby time per QoS to a mobile station via abroadcast message. In the first embodiment of the present invention, aresource allocation standby time is set in consideration of a grantscheduling type among various factors that determine a QoS level forexample. In particular, it is ale to set a resource allocation standbytime in consideration of another factor e.g., latency, etc.) fordetermining a QoS level.

Referring to FIG. 7, a base station broadcasts a resource allocationstandby time per grant scheduling type via SFH [S710].

Table 1 illustrates an example of a resource allocation standby time pergrant scheduling type. In Table 1, a unit of a resource allocationstandby time is set to ms. Alternatively, the unit of the resourceallocation standby time can be set to a subframe, a frame or asuperframe.

TABLE 1 QoS level Resource allocation Grant scheduling type standby time(ms) Unsolicited Grant Service (UGS) 40 real-time Polling Service (rtPS)40 extended-real-time Polling Service (ertPS) 40 nrtPS (non-real-timePolling Service) 100 BE (best effort) 150

In order to transmit data having a characteristic of a real-time PollingService (hereinafter abbreviated ‘rtPS’), a mobile station transmits afirst bandwidth request indicator to the base station [S720] and sets atime of a timer to 40 ms that is a resource allocation standby timecorresponding to the rtPS. In this case, the bandwidth request indicatorincludes a grant scheduling type rtPS, a bandwidth request size and amobile station ID.

If a response is not made by the base station within 40 ms, the mobilestation transmits a second bandwidth request indicator [S730] and sets atime of the timer to 40 ms. If an uplink resource is allocated by thebase station within 40 ms [S740], the mobile station stops the timer andthen transmits data via the allocated resource [S750].

Subsequently, the mobile station transmits a third bandwidth requestindicator for transmitting data having a characteristic of anon-real-time Polling Service (hereinafter abbreviated ‘nrtPS’) to thebase station [S760] and sets a time of the timer to 100 ms that is aresource allocation standby time corresponding to the nrtPS. In thiscase, the bandwidth request indicator includes a grant scheduling typenrtPS, a bandwidth request size 500 and a mobile station ID. If themobile station has an uplink resource allocated thereto from the basestation within 100 ms [S770], the mobile station stops the time and thentransmits the data via the allocated resource [S780].

Now, a method of transmitting a bandwidth request in a wirelesscommunication system according to a first embodiment of the presentinvention in a 5-step scheme is explained with reference to FIG. 8 andFIG. 9 as follows.

FIG. 8 is a diagram for a case of setting a response information standbytime for a BW-REQ message to be equal to a resource allocation standbytime in a 5-step scheme, and FIG. 9 is a diagram for a case of setting aresponse information standby time for a BW-REQ message to be differentfrom a resource allocation standby time in a 5-step scheme. A responseinformation standby time for a BW-REQ message is a waiting time until abandwidth request indicator is retransmitted due to failure in receivingACK/NACK (acknowledgement/negative acknowledgement) for the BW-REQmessage, after the mobile station has transmitted the BW-REQ message.

Referring to FIG. 8 and FIG. 9, a base station broadcasts a resourceallocation standby time per grand scheduling type via SFH [S810, S910].

A mobile station transmits a first bandwidth request indicator to thebase station to transmit data having an nrtPS characteristic [S820,5920] and sets a time of a timer to 100 ms that is a resource allocationstandby time corresponding to nrtPS. In this case, a bandwidth requestindicator includes a grand scheduling type nrtPS, a bandwidth requestsize 100 and a mobile station ID.

If an uplink resource is allocated to the mobile station by the basestation within 100 ms [S830, S930], the mobile station stops the timer,transmits a BW-REQ message via the allocated resource [S840, S940], andsets a time of the timer to a response information standby time for theBW-REQ message. In doping so, the response information standby time forthe BW-RREQ message can be set to 100 ms that is the resource allocationstandby time, as shown in FIG. 8, or can be set to a value differentfrom the resource allocation standby time 100 ms, as shown in FIG. 9.

If the mobile station fails to receive response information for theBW-REQ message within the response information standby time for theBW-REQ message, the mobile station retransmits a second bandwidthrequest indicator [S860, S960].

In the following description, a method of performing a bandwidth requestprocess in a wireless communication system according to a secondembodiment of the present invention is explained with reference to FIG.10.

FIG. 10 is a diagram for a method of performing a bandwidth requestprocess in a wireless communication system according to a secondembodiment of the present invention in a 3-step scheme.

According to a second embodiment of the present invention, a basestation transmits a per-index resource allocation standby time and anindex of a resource allocation standby time corresponding to acorresponding connection via MAC message.

Referring to FIG. 10, a base station transmits a per-index resourceallocation standby time via SFH [S1010].

Table 2 shows an example of a per-index resource allocation standbytime. In Table 2, a unit of a resource allocation standby time is set to‘ms’. Yet, the unit of the resource allocation standby time can be setto a subframe, a frame or a superframe.

TABLE 2 Resource allocation Index standby time 1 40 2 100 3 150 4 200

In order to generate a dynamic service connection, a mobile stationsends a dynamic service addition request (hereinafter abbreviatedDSA-REQ) message to the base station [S1020]. In this case, the DSA-REQmessage can include QoS level information of data the mobile stationattempts to transmit. In FIG. 10, the DSA-REQ message includes a grantscheduling type rtPS for example of the QoS level information.

The base station informs the mobile station of an index 1 of a stand bytime for allocation of a resource, which is to be used by the mobilestation, via a dynamic service addition response (hereinafterabbreviated DSA-RSP) message in response to the DSA-REQ message [S1030].

In order to transmit data having a real time polling servicecharacteristic, the mobile station transmits a first bandwidth requestindicator to the base station [S1040] and sets a time of a timer to 40ms that is a resource allocation standby time corresponding to theindex 1. In this case, the bandwidth request indicator includes an index1, a bandwidth request size 100 and a mobile station ID.

If there is no response from the base station within 40 ms, the mobilestation transmits a second bandwidth request indicator [S1050] and thensets a time of the timer to 40 ms. If an uplink resource is allocated tothe mobile station by the base station within 40 ms [S1060], the mobilestation stops the timer and then transmits the data via the allocatedresource [S1070].

A bandwidth request transmitting method in a wireless communicationsystem according to a second embodiment of the present inventionprovides the following advantage. Namely, a same resource allocationstandby time is not applied to a mobile station having a same QoS levelbut a resource allocation standby time can be differently applied to amobile station having a same QoS level according to a situation of abase station.

In a first or second embodiment of the present invention, when a basestation transmits a resource allocation standby time per grantscheduling type or a resource allocation standby time per index to amobile station, the base station is able to transmit a value of theresource allocation standby time itself or a difference value from adefault value by predetermining the default value of the resourceallocation standby time per QoS or index.

FIG. 19 is a diagram for a data format of a difference value if aresource allocation standby time is transmitted in form of thedifference value from a default value.

Referring to FIG. 19, a sign field is the field that indicates whether aresource allocation standby time is greater or smaller than a defaultvalue. If the sign field exists, a value field indicates a differencebetween a default value and a resource allocation standby time. If thesign field does not exist, a value field indicates a value resultingfrom subtracting a default value from a resource allocation standbytime.

For instance, if a value of a resource allocation standby time isgreater than a default value, assume that a sign field is set to 1. If avalue of a resource allocation standby time is smaller than a defaultvalue, assume that a sign field is set to 0. When a default value is 40ms, if a resource allocation standby time value a base station is goingto transmit to a mobile station is 46 ms, a sign field is set to 1 and avalue field is set to 6 ms.

In this case, the value field can be represented by a generalexpression, a power expression or a step expression.

In the general expression, a value to be transmitted is expressed as abinary number. For instance, a value to be transmitted is 6 ms, a valuefield is expressed as 110.

In the power expression, a value to be transmitted is converted to anexponent of a predetermined value to express the exponent as a binarynumber. For instance, if a predetermined value is 2 and a value to betransmitted is 64 ms, as 64 is equal to 2⁶, a value field is expressedas 110 that is a binary number of 6.

In the step expression, a value is converted to a multiple of apredetermined value to express the multiple as a binary number. Forinstance, if a predetermined value is 5 and a value to be transmitted is30 ms, as 30 is equal to 5*6, a value field is expressed as 110 that isa binary number of 6.

A default value of a resource allocation standby time per QoS or indexcan be known to a mobile station and a base station in advance or can benotified via SFH to a mobile station by a base station. And, adifference between a resource allocation standby time and a defaultvalue can be notified to a mobile station by a base station via SFH orMAC message.

For instance, assume that a default value of a per-index resourceallocation standby time has the value shown in Table 2. Assume that aper-index resource allocation standby time a base station is gong totransmit to a mobile station has the value shown in Table 3. Assume thata data format of a difference value between a default value and aresource allocation standby time used a format including a value fieldonly by expressing the difference value as 3 bits. And, assume that 10ms-step expression is used.

On the above assumptions, a resource allocation standby timecorresponding to an index 1 is 40 and has a difference from a defaultvalue set to 0. ‘0’ is equal to a zero time of 10. And, ‘zero’ can beexpressed as a binary number of ‘000’.

A resource allocation standby time corresponding to an index 2 is 110and has a difference from a default value set to 10. ‘10’ is equal toone time of 10. And, ‘one’ can be expressed as a binary number of ‘001’.

A resource allocation standby time corresponding to an index 3 is 170and has a difference from a default value set to 20. ‘20’ is equal totwo times of 10. And, ‘two’ can be expressed as a binary number of‘010’.

A resource allocation standby time corresponding to an index 4 is 230and has a difference from a default value set to 30. ‘30’ is equal tothree times of 10. And, ‘three’ can be expressed as a binary number of‘011’.

Therefore, the base station transmits 000001010011 to the mobilestation.

TABLE 3 Resource allocation Index standby time 1 40 2 110 3 170 4 230

A method of transmitting a bandwidth request in a wireless communicationsystem is explained with reference to FIGS. 11 to 14 as follows.According to a third embodiment of the present invention, a base stationtransmits a resource allocation standby time, which is to be used by amobile station, to the mobile station via a MAC message.

In this case, the base station able to transmit a resource allocationstandby time to be used by the mobile station in consideration of datathe mobile station is going to transmit or is able to transmit aresource allocation standby time set. The resource allocation standbytime set can include a resource allocation standby time per grantscheduling type shown in Table 1 or a resource allocation standby timeper service type. Table 4 shows an example of a resource allocationstandby time per service type.

TABLE 4 QoS level Resource allocation Service type standby time Realtime service 40 Non-real time service 100

In the following description, explained is a case that a base stationtransmits a resource allocation standby time, which is to be used by amobile station, in consideration of data the mobile station is going totransmit.

FIG. 11 is a diagram for a case of using a DSA-RSP message in a methodof performing a bandwidth request process in a wireless communicationsystem according to a third embodiment of the present invention.

Referring to FIG. 11, in order to generate a dynamic service connection,a mobile station sends a DSA-REQ message to a base station [S1110]. Inthis case, the DSA-REQ message includes a grant scheduling type ‘rtPS’of data the mobile station is going to transmit.

Since the rtPS is a real-time service, the base station informs themobile station of 40 ms, which is a resource allocation standby time tobe used by the mobile station, via a DSA-RSP message [S1120].

The mobile station transmits a first bandwidth request indicator to thebase station to transmit data having a real time polling servicecharacteristic [S1130] and sets a time of a timer to 40 ms that is aresource allocation standby time received from the base station. In thiscase, the bandwidth request indicator includes a service type real timeservice, a bandwidth request size 100 and a mobile station ID.

If there is no response from the base station within 40 ms, the mobilestation transmits a second bandwidth request indicator [S1140] and setsa time of the timer to 40 ms. If an uplink resource is allocated to themobile station within 40 ms [S1150], the mobile station stops the timerand then transmits the data via the allocated resource [S1160].

FIG. 12 is a diagram for a case of using a DNG-RSP message in a methodof performing a bandwidth request process in a wireless communicationsystem according to a third embodiment of the present invention.

Referring to FIG. 12, a mobile station sends an RNG-REQ message to abase station to perform an initial network entry [S1210]. The basestation informs the mobile station of 40 ms, which is a resourceallocation standby time to be used for signaling data transmission bythe mobile station, via an RNG-RSP message in response to the RNG-REQmessage [S1220].

The mobile station transmits a first bandwidth request indicator to thebase station to transmit signaling data having a real time pollingservice characteristic [S1230] and sets a time of a timer to 40 ms thatis a resource allocation standby time received from the base station. Inthis case, the bandwidth request indicator includes a bandwidth requestsize 100 and a mobile station ID.

If there is no response from the base station within 40 ms, the mobilestation transmits a second bandwidth request indicator [S1240] and setsa time of the timer to 40 ms. If an uplink resource is allocated to themobile station within 40 ms [S1250], the mobile station stops the timerand then transmits the data via the allocated resource [S1260].

In the following description, a method of transmitting a bandwidthrequest for setting a resource allocation standby time in accordancewith a priority of a mobile station to provide a differentiated servicecorresponding to the priority of the mobile station is explained withreference to FIGS. 13 to 15.

First of all, a base station can be aware of a priority of a mobilestation via a MAC message or an uplink allocation request message.

The base station is able to determine the priority of the mobile stationusing a MAC address or a mobile station ID carried on such a MAC messageas an RNG-REQ message and a DSA-REQ message. Since the MAC message isdelivered via an uplink resource allocated to the mobile station by thebase station, the base station is able to know which mobile station hassent the MAC message through the resource carrying the MAC message.Therefore, the base station is able to determine the priority of themobile station.

In a contention based 3-step scheme, it is able to know a priority of amobile station via a mobile station ID carried on a bandwidth requestindicator. In a contention based 5-step scheme, it is able to know apriority of a mobile station via a mobile station ID carried on a BW-REQmessage. In a non-contention based scheme, it is able to know a priorityof a mobile station via such a dedicated resource of a mobile station asa code, a resource region and the like.

First of all, a method of transmitting bandwidth request informationusing a resource allocation standby time determined according to apriority of a mobile station without considering a QoS level of data isexplained with reference to FIG. 13 as follows. FIG. 13 is a diagram fora method of transmitting a bandwidth request using one resourceallocation standby time applicable to all connections of one mobilestation.

Referring to FIG. 13, a mobile station sends an RNG-REQ message to abase station [S1310]. The base station determines a priority of themobile station using a MAC address included in the RNG-REQ message andthen informs the mobile station of a resource allocation standby time ofthe mobile station according to the priority via an RNG-RSP message[S1320]. For instance, if a resource allocation standby time of a mobilestation having a priority 1 is 50 ms, a resource allocation standby timeof a mobile station having a priority 2 is 150 ms, and a priority of amobile station having sent an RNG-REQ message is 1, the base stationinforms the mobile station of 50 ms via an RNG-RSP message.

The mobile station transmits a first bandwidth request indicator to thebase station to transmit data having a real time polling servicecharacteristic [S1330] and then sets a time of a timer to 50 ms that isthe resource allocation standby time received from the base station. Inthis case, the bandwidth request indicator includes a grant schedulingtype rtPS, a bandwidth request size 100 and a mobile station ID. Ifthere is no response within 50 ms from the base station, the mobilestation transmits a fourth bandwidth request indicator [S1360].

Table 5 shows an example of a resource allocation standby time accordingto a grant scheduling type and priority as factors for determining a QoSlevel. In Table 5, a unit of a resource allocation standby time isrepresented as ‘ms’. Yet, the unit of the resource allocation standbytime can be set to a subframe, a frame or a superframe.

Referring to Table 5, it is able to set a resource allocation standbytime for an emergency service or control signaling message to a fixedvalue.

TABLE 5 QoS level Grant scheduling Resource allocation Value typePriority standby time (ms) 0000 Emergency — 50 0001 Control signaling —50 0010 UGS — 50 0011 rtPS High 50 0100 rtPS Low 100 0101 ertPS — 500110 nrtPS High 150 0111 nrtPS Low 250 1000 BE — 300

Table 6 or Table 7 shows an example of a resource allocation standbytime according to a service type and priority as factors for determininga QoS level. In Table 6 or Table 7, a unit of a resource allocationstandby time is represented as ‘ms’. Yet, the unit of the resourceallocation standby time can be set to a subframe, a frame or asuperframe. Service types can be classified into a real time service anda non-real time service. Alternatively, service types can be classifiedinto a delay sensitive service and a delay tolerant service.

In case of requesting an uplink resource for an emergency service or acontrol signaling message, a mobile station uses a resource allocationstandby time corresponding to ‘real-time service’ and ‘High’ shown inTable 6 or ‘delay sensitive service’ and ‘High’ priority shown in Table7.

TABLE 6 QoS level Resource allocation Value Service type Prioritystandby time (ms) 00 real-time service High 50 01 real-time service Low100 10 non real-time service High 200 11 non real-time service Low 250

TABLE 7 QoS level Resource allocation Value Service type Prioritystandby time (ms) 00 delay sensitive service High 50 01 delay sensitiveservice Low 100 10 delay tolerant service High 200 11 delay tolerantservice Low 250

FIG. 14 is a diagram for transmitting a resource allocation standby timedetermined according to a QoS level via additional broadcast informationand a MAC message.

Referring to FIG. 14, a base station transmits a resource allocationstandby time corresponding to a QoS level of data to transmit via MACmessages (RNG-REQ, RNG-RSP) exchanged in the course of performingranging or MAC messages (DSA-REQ, DSA-RSP) exchanged in the course ofgenerating a dynamic service.

And, the base station transmits a resource allocation standby timedetermined according to a QoS level in a manner that the resourceallocation standby time is included in the additional broadcastinformation. In this case, an unchangeable resource allocation standbytime value may not be included in the additional broadcast information.Resource allocation standby times are not changed within a transmissioninterval of the additional broadcast information.

In the following description, a method of transmitting bandwidth requestinformation using a resource allocation standby time determinedaccording to a QoS level of data and a priority of a mobile station isexplained with reference to FIG. 15.

FIG. 15 is a diagram for a method of transmitting a bandwidth requestusing a resource allocation standby time according to a QoS level for aplurality of connections of one mobile station having a high priority.

Referring to FIG. 15, a mobile station sends a DSA-REQ message to a basestation [S1501]. The base station informs the mobile station of aresource allocation standby time according to a priority of the mobilestation and a grant scheduling type of data, which is to be transmittedby the mobile station, via a DSA-RSP message [S1502]. Assuming that theresource allocation standby time shown in

Table 5 is used, if a grant scheduling type of data to be transmitted isrtPS and a priority of the scheduling type is ‘High’, a mobile stationis informed of 50 ms via a DSA-RSP message.

The mobile station transmits a first bandwidth request indicator to thebase station to transmit data having a real time polling servicecharacteristic [S1503] and sets a time of a timer to 50 ms, which is theresource allocation standby time received from the base station. In thiscase, the bandwidth request indicator includes a grant scheduling typertPS, a bandwidth request size 100 and a mobile station ID. If there isno response from the base station within 50 ms, the mobile stationtransmits a second bandwidth request indicator [S1504].

Subsequently, the mobile station sends a DSA-REQ message to the basestation [S1505]. The base station then informs the mobile station of‘300 ms’, which is a resource allocation standby time corresponding to aBE of the mobile station having a priority, via a DSA-RSP message.

In the following description, a method of transmitting a bandwidthrequest in a wireless communication system according to a fourthembodiment of the present invention is explained with reference to FIG.16. According to a fourth embodiment of the present invention, a basestation does not inform a mobile station of a resource allocationstandby time but the mobile station uses a per-QoS resource allocationstandby time previously determined in a wireless communication system.For instance, a resource allocation standby time corresponding to rtPSis 50 ms and a resource allocation standby time corresponding to nrtPSis 100 ms.

The per-QoS resource allocation standby time is determined by QoS levelwhich is transmitted through a DSA-REQ message or a DSC-REQ message. QoSlevel is determined by Qos parameters and mobile station's priority andreferred to as service class or access class. QoS level can be mapped toQoS information which is included in a quick access message with STID in3-step BR procedure.

FIG. 16 is a diagram of a method of transmitting a bandwidth request ina wireless communication system according to a fourth embodiment of thepresent invention.

Referring to FIG. 16, a mobile station transmits a first bandwidthrequest indicator to a base station to transmit data having a real timepolling service characteristic [S1601] and sets a time of a timer to ‘50ms’, which is a previously determined resource allocation standby timecorresponding to rtPS. In this case, the bandwidth request indicatorincludes a grant scheduling type rtPS, a bandwidth request size 100 anda mobile station ID. If there is no response from the base stationwithin 50 ms, the mobile station transmits a second bandwidth requestindicator [S1602].

The mobile station transmits a third bandwidth request indicator to thebase station to transmit data having a non-real time polling servicecharacteristic [S1603] and sets a time of a timer to ‘100 ms’, which isa previously determined resource allocation standby time correspondingto nrtPS. In this case, the bandwidth request indicator includes a grantscheduling type rtPS, a bandwidth request size 100 and a mobile stationID. If there is no response from the base station within 100 ms, themobile station transmits a fourth bandwidth request indicator [S1604].

In the following description, after a base station has received abandwidth request indicator or a BW-REQ message, a process forallocating a resource to a mobile station for a resource allocationstandby time determined in consideration of a resource allocationstandby time of the mobile station.

FIG. 17 is a flowchart of a process for resource allocation in a basestation.

Referring to FIG. 17, a base station receives a bandwidth requestindicator or a BW-REQ message from a mobile station [S1701] and thendecodes the received indicator or message.

Once the bandwidth request indictor or the BW-REQ message is normallydecoded, the base station sends an ACK message to the mobile station[S1703 a]. If the bandwidth request indictor or the BW-REQ message isnot normally decoded, the base station sends a NACK message to themobile station [S1703 b]. Optionally, the steps S1703 a and S1703 b oftransmitting response information can be skipped.

The base station discovers a resource allocation standby time used bythe mobile terminal by checking such a parameter as a QoS level and atimer index contained in the bandwidth request indicator or BW-REQmessage [S1704] and then sets a time of a timer by calculating aresource allocation time from the resource allocation standby time usedby the mobile station [S1705]. For instance, if the resource allocationstandby time of the mobile station is set to 40 ms, the base station isable to use a value resulting from subtracting a roundtrip delay or thelike from 40 ms as a resource allocation standby time.

A scheduler of the base station determines whether to allocate aresource [S1706]. If the resource allocation is possible [S1707], thebase station allocates the resource to the mobile station [S1708].Otherwise, the base station checks whether the timer expires [S1709]. Ifthe timer expires, the resource allocation is terminated. If the timerdoes not expire, it is determined again whether to allocate theresource. In particular, the base station keeps determining whether toallocate the resource until the timer is terminated.

Now, after a mobile station has received response information for abandwidth request indicator, a case of setting a timer is explained withreference to FIG. 18 as follows. FIG. 18 is a diagram for a case ofsetting a timer after a mobile station has received response informationin response to a bandwidth request indicator.

Referring to FIG. 18, a base station broadcasts a resource allocationstandby time per grand scheduling type via SFH [S1801]. A mobile stationtransmits a first bandwidth request indicator to the base station totransmit data having an nrtPS characteristic [S1802] and then receivesresponse information in response to all bandwidth request indicatorsreceived by the base station [S1803]. If the transmission of thebandwidth request indicator transmitted by the mobile station fails, themobile station transmits a second bandwidth request indicator [S1804].

The mobile station receives response information in response to allbandwidth request indicators received by the base station [S1805].

If the mobile station confirms that the transmission of the bandwidthrequest indicator transmitted by the mobile station is successful, themobile station sets a time of a timer to ‘100 ms’ that is a resourceallocation standby time corresponding to nrtPS.

If a resource is allocated by the base station within 100 ms [S1806],the mobile station transmits data via the allocated resource [S1807]. Ifthe resource is not allocated by the base station within 100 ms, themobile station retransmits the bandwidth request indicator. In thiscase, it is ale to limitation on a count of the retransmission.

In the following description, a method of transmitting/receivingACK/NACK in a wireless communication system according to an embodimentof the present invention is explained with reference to FIGS. 20 to 25.According to an embodiment of the present invention, a base stationreceives a bandwidth request indicator or a ranging indicator from amobile station and then transmits acknowledgement (hereinafterabbreviated ‘ACK’), for example, by which the present invention isnon-limited. The present invention is applicable to a case that a basestation receives a random access code and then transmits ACK in responseto the received random access code.

In a method of transmitting and receiving ACK according to an embodimentof the present invention, a base station transmits ACK from one locationspaced apart from another location, where the base station has receiveda bandwidth request indicator or a ranging indicator, by a specificvalue. According to this embodiment of the present invention, a intervalbetween the location, where the base station has received a bandwidthrequest indicator or a ranging indicator, and a timing point oftransmitting the ACK to the mobile station is named an ACK delay. Inthis case, the ACK delay can be defined by a unit of frame, subframe or‘ms’. Subsequently, the mobile station checks whether the ACK isreceived at a timing point determined by the ACK delay only.

According to an embodiment of the present invention, if a base stationtransmits an ACK from one location spaced apart from another location,where the base station has received a bandwidth request indicator or aranging indicator, by an ACK delay, it is not necessary for the basestation to have the bandwidth request or ranging indicator receivedlocation information included within the ACK separately. Therefore, itis able to reduce an overhead. In this case, the bandwidth request orranging indicator received location information means information ofsuch as a time axis for receiving the bandwidth request indicator or theranging indicator as a superframe, a frame, a subframe and the like.

Thus, both of the base station and the mobile station should be aware ofthe ACK delay value. For this, the base station can inform the mobilestation of the ACK delay value or a preset ACK delay value can be used.

In the following description, explained is a case that a base stationinforms a mobile station of an ACK delay value. First of all, a basestation is able to inform a mobile station of an ACK delay value bybroadcasting or unicasting.

When a base station base station informs a mobile station of an ACKdelay value by broadcasting, the mobile station is informed of the ACKdelay value via a secondary superframe header (hereinafter abbreviated‘S-SFH’. In doing so, the base station is able to transmit the ACK delayvalue to the mobile station together with parameters related to abandwidth request via S-SFH sub-packet carrying the parameters relatedto the bandwidth request.

Moreover, the base station is able to transmit the ACK delay value tothe mobile station together with parameters related to an initialranging via S-SFH sub-packet carrying the parameters related to theinitial ranging.

Besides, it is able to inform a mobile terminal of an ACK delay value bybroadcasting on a traffic channel. A base station is able to transmitsystem information, which is not carried on a superframe header(hereinafter abbreviated ‘SFH’), to a mobile station via a trafficchannel. In doing so, an ACK delay value can be carried on the trafficchannel together with the system information.

The system information, which is not carried on the SFH, includesadditional broadcast information. For instance, the additional broadcastinformation includes handover relevant information, MIMO (multi-inputmulti-output) relevant information, relay relevant information,multi-carrier relevant information, femto-cell relevant information,EMBS (enhanced multicast and broadcast service) relevant information,inter-rat relevant information, neighbor advertisement relevantinformation, etc.

The handover relevant information includes a codebook subset for PMI(precoding matrix indicator) configuration and a codebook subset for DLMU-MIMO (downlink multi-user MIMO) subset indication.

The relay relevant information includes hop information, DL/UL(downlink/uplink) allocation, transmit/receive zone and zone type.

The multi-carrier relevant information includes carrier index,fully/partially configured carrier indication, center frequency,bandwidth information, initial access ability and guard resourceinformation.

The EMBS relevant information includes service ID and MSCCH resourceallocation information. The inter-rat relevant information includes MIH(media independent handover) capability support. And, the neighboradvertisement relevant information includes characteristics of neighborBS (base station).

In case that a base station informs a mobile station of an ACK delayvalue by unicasting, it is able to deliver the ACK delay value via a MACmanagement message in an initial network entry process. The MACmanagement message includes a ranging response message, a registrationresponse message (REG-RSP message), a SS basic capability responsemessage (SBC-RSP message), a dynamic service addition response message(DSA-RSP message, a dynamic service change response message (DSC-RSPmessage), etc.

In case that a preset delay value is used between a base station and amobile station, the base station does not perform a process fordelivering an ACK delay value to the mobile station separately buttransmits ACK/NACK to the mobile station at one location spaced apartfrom another location, where a bandwidth request indicator or a rangingindicator was received, by a preset ACK delay value.

FIG. 20 is a flowchart for a method of receiving ACK/NACK in a wirelesscommunication system according to an embodiment of the presentinvention.

Referring to FIG. 20, a base station allocates an uplink (UL) region fortransmitting a bandwidth request indicator or an uplink region fortransmitting a ranging indicator to a mobile station [S2010]. The mobilestation then transmits the bandwidth request indicator or the rangingindicator to the base station via the allocated region [S2020].

In this case, the uplink (UL) region for transmitting the bandwidthrequest indicator and the uplink region for transmitting the rangingindicator separately exist. Each of the uplink regions includes at leastone transmission opportunity. In this case, the transmission opportunitymeans a resource region including at least one resource unit and canhave an index.

FIG. 21( a) is a diagram of a transmission opportunity set if atransmission opportunity is allocated by a subframe unit, and FIG. 21(b) is a diagram of a transmission opportunity set if a transmissionopportunity is allocated by a frame unit.

Referring to FIG. 21( a), a transmission opportunity is assigned to aradio resource per subframe. Referring to FIG. 21( b), transmissionopportunities are assigned to a radio resource throughout a whole frame.In particular, in case that a transmission opportunity is assigned by aframe unit, one transmission opportunity can be assigned across twosubframes.

Meanwhile, a base station transmits information on a transmissionopportunity set to a mobile station via S-SFH.

In case that a transmission opportunity is assigned by a subframe unit,a base station transmits information on a transmission opportunity setof each subframe within four frames included in one superframe to amobile station. The information on the transmission opportunity set ofeach subframe can include a frame index or bitmap, a subframe index orbitmap, a resource start offset and a transmission opportunity number.In particular, a base station explicitly informs a mobile station of anindex of a frame having a transmission opportunity assigned thereto orcan transmit a frame bitmap for setting a bit position of antransmission opportunity assigned frame to ‘1’ to a mobile station.Moreover, a base station explicitly informs a mobile station of an indexof a subframe having a transmission opportunity assigned thereto or cantransmit a subframe bitmap for setting a bit position of an transmissionopportunity assigned frame to ‘1’ to a mobile station. Besides, a basestation is able to assign a transmission opportunity to a previouslydetermined frame or subframe. In this case, the base station needs notto inform a mobile station of information on a transmission opportunityassigned frame or subframe.

In case that a transmission opportunity is assigned by a frame unit, abase station transmits information on a transmission opportunity set ofeach of four frames included in one superframe. The information on thetransmission opportunity of each of the frames can include a frame indexor bitmap, a resource start offset and a transmission opportunitynumber. In particular, the base station explicitly informs the mobilestation of an index of a transmission opportunity assigned frame or cantransmit a frame bit map having a bit position of a transmissionopportunity assigned frame to ‘1’ to the mobile station.

Referring now to FIG. 20, the mobile station receives the ACK/NACK fromthe base station via a region spaced apart from the timing point, atwhich the base station received the bandwidth request indicator or theranging indicator, by the ACK delay [S2030].

The ACK delay can be defined by a subframe or frame unit. In thefollowing description, a case of defining an ACK delay by a subframeunit and a case of defining an ACK delay by a frame unit in case ofassigning a transmission opportunity by a subframe unit or a frame unitare explained.

First of all, in case that a transmission opportunity is assigned by asubframe unit, a case of defining an ACK delay by a subframe unit isexplained with reference to FIG. 22 as follows.

FIG. 22( a) is a diagram for an ACK transmission timing point if atransmission opportunity is assigned by a subframe unit and an ACK delayis defined by a subframe unit, when a ratio of a downlink versus anuplink is 5:3. And, FIG. 22( b) is a diagram for an ACK transmissiontiming point if a transmission opportunity is assigned by a subframeunit and an ACK delay is defined by a subframe unit, when a ratio of adownlink versus an uplink is 4:4.

In FIG. 22( a) and FIG. 22( b), shown is that an ACK delay value is 5subframes.

Referring to FIG. 22( a), a mobile station transmits a bandwidth requestindicator or a ranging indicator in a first uplink subframe of a framen. And, a base station transmits ACK in a third downlink subframe of aframe n+1 spaced apart from the subframe, in which the mobile stationtransmitted the bandwidth request indicator or the ranging indicator, by5 subframes. Since the mobile terminal is already aware of an ACK delayvalue, it checks the ACK in the third downlink subframe of the framen+1.

Referring to FIG. 22( b), a mobile station transmits a bandwidth requestindicator or a ranging indicator in a first uplink subframe of a framen. And, a base station transmits ACK in a second downlink subframe of aframe n+1 spaced apart from the subframe, in which the mobile stationtransmitted the bandwidth request indicator or the ranging indicator, by5 subframes. Since the mobile terminal is already aware of an ACK delayvalue, it checks the ACK in the second downlink subframe of the framen+1.

In case that a transmission opportunity is assigned by a subframe unit,a case of defining an ACK delay by a frame unit is explained withreference to FIG. 23 as follows.

FIG. 23( a) is a diagram for an ACK transmission timing point if atransmission opportunity is assigned by a subframe unit and an ACK delayis defined by a frame unit, when a ratio of a downlink versus an uplinkis 5:3. And, FIG. 23( b) is a diagram for an ACK transmission timingpoint if a transmission opportunity is assigned by a subframe unit andan ACK delay is defined by a frame unit, when a ratio of a downlinkversus an uplink is 4:4.

In FIG. 23( a) and FIG. 23( b), shown is that an ACK delay value is 2frames.

Referring to FIG. 23( a), a mobile station transmits a bandwidth requestindicator or a ranging indicator in a first uplink subframe of a framen. And, a base station transmits ACK in a frame n+2 spaced apart from atiming point, at which the mobile station transmitted the bandwidthrequest indicator or the ranging indicator, by 2 frames.

In this case, the base station is able to transmit the ACK via asubframe determined according to the subframe, in which the mobilestation transmitted the bandwidth request indicator or the rangingindicator, of the frame spaced apart from the frame, in which the mobilestation transmitted the bandwidth request indicator or the rangingindicator, by the ACK delay value. Alternatively, the base station isable to transmit the ACK via a random subframe of the frame spaced apartfrom the frame, in which the mobile station transmitted the bandwidthrequest indicator or the ranging indicator, by the ACK delay value. Forinstance, if a mobile station transmits a bandwidth request indicator ora ranging indicator via a first subframe of a frame n, a base station isable to transmit ACK to the mobile station via a first subframe of aframe n+2 or a random subframe of the frame n+2.

In case that the base station transmits ACK via a subframe determinedaccording to a subframe in which the base station received a bandwidthrequest indicator or a ranging indicator, the mobile station checks thecorresponding subframe only. In case that the base station transmits ACKvia a random subframe within a frame spaced apart from a frame, in whichthe base station received a bandwidth request indicator or a rangingindicator, by an ACK delay, the mobile station checks the ACK from afirst subframe of a frame spaced apart from a frame, from which thebandwidth request indicator or the ranging indicator was transmitted, bythe ACK delay.

Referring to FIG. 23( b), a mobile station transmits a bandwidth requestindicator or a ranging indicator in a first uplink subframe of a framen. And, a base station transmits ACK via a frame n+2 spaced apart from atiming point, at which the mobile station transmitted the bandwidthrequest indicator or the ranging indicator, by 2 frames.

In the following description, if a transmission opportunity is assignedby a frame unit, explained with reference to FIG. 24 is a case that anACK delay is defined by a subframe unit

FIG. 24 is a diagram for an ACK transmission timing point if atransmission opportunity is assigned by a frame unit and an ACK delay isdefined by a subframe unit, when a ratio of a downlink versus an uplinkis 4:4.

In FIG. 24, shown is that an ACK delay value is 5 subframes.

Referring to FIG. 24, a mobile station transmits a bandwidth requestindicator or a ranging indicator in a first uplink subframe of a framen. And, a base station transmits ACK in a second subframe of a frame n+1spaced apart from a timing point, at which the mobile stationtransmitted the bandwidth request indicator or the ranging indicator, by5 subframes. Since the mobile terminal is already aware of an ACK delayvalue, it checks the ACK in the second downlink subframe of the framen+1.

FIG. 25 is a diagram for an ACK transmission timing point if atransmission opportunity is assigned by a frame unit and an ACK delay isdefined by a frame unit, when a ratio of a downlink versus an uplink is4:4.

In FIG. 25, shown is that an ACK delay value is 2 frames.

Referring to FIG. 25, a mobile station transmits a bandwidth requestindicator or a ranging indicator in a frame n. And, a base stationtransmits ACK via a frame n+2 spaced apart from a timing point, at whichthe mobile station transmitted the bandwidth request indicator or theranging indicator, by 2 frames.

In this case, the base station is able to transmit the ACK via asubframe determined according to the subframe, in which the mobilestation transmitted the bandwidth request indicator or the rangingindicator, of the frame spaced apart from the frame, in which the mobilestation transmitted the bandwidth request indicator or the rangingindicator, by the ACK delay value. Alternatively, the base station isable to transmit the ACK via a random subframe of the frame spaced apartfrom the frame, in which the mobile station transmitted the bandwidthrequest indicator or the ranging indicator, by the ACK delay value. Forinstance, if a mobile station transmits a bandwidth request indicator ora ranging indicator via a first subframe of a frame n, a base station isable to transmit ACK to the mobile station via a first subframe of aframe n+2 or a random subframe of the frame n+2.

In case that the base station transmits ACK via a subframe determinedaccording to a subframe in which the base station received a bandwidthrequest indicator or a ranging indicator, the mobile station checks thecorresponding subframe only. In case that the base station transmits ACKvia a random subframe within a frame spaced apart from a frame, in whichthe base station received a bandwidth request indicator or a rangingindicator, by an ACK delay, the mobile station checks the ACK from afirst subframe of a frame spaced apart from a frame, from which thebandwidth request indicator or the ranging indicator was transmitted, bythe ACK delay.

In case that a base station fails to detect a failure of a reception ofa bandwidth request indicator or a ranging indicator at a specifictiming point, the base station is able to determine whether to transmitan ACK according to the number of detected indicators. In particular, ifthe number of the detected indicators is small and a resource can beallocated to all indicators within a minimum timer value, the basestation may not transmit the ACK. If there exist lots of detectedindicators, in case that information of a resource, which is to beallocated to a plurality of indicators, is transmitted at a timing pointof transmitting ACK, the base station is able to transmit the ACK.

A random access method in a wireless communication system according toan embodiment of the present invention is explained as follows.

First of all, in a random access method in a wireless communicationsystem according to an embodiment of the present invention, a randomaccess method of a mobile station varies according to whether a basestation supports an acknowledgement (hereinafter abbreviated ACK) for abandwidth request indicator, a quick access message or a bandwidthrequest message.

Therefore, it is necessary for a base station to inform a mobile stationwhether an ACK is supported. For this, the base station is able toinform the mobile station of a presence or non-presence of ACK supportby broadcast or unicast. If a presence or non-presence of ACK support isdefined in advance, the base station needs not to announce a presence ornon-presence explicitly.

FIG. 26 is a diagram for a case that a base station informs a mobilestation whether ACK is supported by broadcast.

Referring to FIG. 26, a base station is able to inform a mobile stationof a presence or non-presence of ACK support via a secondary superframeheader (hereinafter abbreviated S-SFH).

A base station transmits a bandwidth request (BR) ACK support fieldtogether with parameters related to a bandwidth request. In this case,the parameters related to the bandwidth request include a bandwidthrequest (BR) channel allocation periodicity, a bandwidth request (BR)subframe allocation bitmap, a bandwidth request (BR) subframe allocationbitmap, a bandwidth request (BR) start offset, a bandwidth request (BR)resource frequency duration, etc.

If the bandwidth request ACK support field is set to 0b0, it means thatthe base station does not support the ACK. If the bandwidth request ACKsupport field is set to 0b1, it means that the base station supports theACK.

FIG. 27 is a diagram for a case that a base station informs a mobilestation whether ACK is supported by unicast.

Referring to FIG. 27, a base station informs a mobile station of apresence or non-presence of ACK support via a MAC management message ofa network entry process.

In particular, the base station is able to inform the mobile station ofa presence or non-presence of the ACK support via an advanced airinterface ranging response (hereinafter abbreviated ‘AAI_RNG_RSP’)message in the network entry process, an advanced air interface SS basiccapability response (hereinafter abbreviated ‘AAI_SBC_RSP’) message, oran advanced air interface registration response (hereinafter abbreviated‘AAI_REG_RSP’) message.

In case that a presence or non-presence of ACK support is announced viathe AAT_RNG_RSP message, the base station receives an initial rangingcode from the mobile station and then transmits the AAI_RNG-RSP messageto announce a presence or non-presence of ACK support. Alternatively,the base station is able to inform the mobile station of a presence ornon-presence of ACK support via the AAI_RNG-RSP message delivered inresponse to the AAI_RNG-REQ (advanced air interface ranging request)message of the mobile station.

If the base station supports the ACK, the base station receives abandwidth request indicator and then transmits an AC after duration ofan ACK delay. In this case, the ACK delay means an interval between aposition, at which the base station receives the bandwidth requestindicator, and a timing point of transmitting the ACK to the mobilestation from the base station. After the base station has received thebandwidth request indicator, if the base station allocates an uplinkresource to the mobile station, the base station may not transmit theACK to the mobile station.

The ACK can be classified into an ack-based ACK, which is transmitted incase that a base station normally receives a bandwidth requestindicator, and a nack-based NACK, which is transmitted in case that abase station fails to normally receive a bandwidth request indicator. Inparticular, the ack-based ACK is transmitted to mobile stations if anormally received code exists. Yet, the nack-based NACK is transmittedto mobile stations if a normally received code fails to exist. In thiscase, the ACK can be transmitted according to whether a quick access isdecoded.

A random access method according to a first embodiment of the presentinvention is explained with reference to FIGS. 28 to 32 as follows.

According to a first embodiment of the present invention, a base stationactivates a timer according to an ACK of a base station and then waitsfor an uplink resource allocation.

First of all, in the following description, explained is a case that amobile station transmits a bandwidth request indicator and a quickaccess message to a base station.

If a mobile station is explicitly or implicitly aware that a basestation has successfully decoded the bandwidth request indicator and thequick access message transmitted by the mobile station, the mobilestation starts a differentiated timer determined according to acharacteristic of data the mobile station is going to transmit. That is,the differentiated timer is defined for a service flow between themobile station and the base station.

The differentiated timer is determined based on such a service flowparameter as an uplink allocation scheduling type, a maximum latency andthe like in a connection setting or operating process. The mobilestation is able to propose a value of the differentiated timer via anadvanced air interface dynamic service addition request (hereinafterabbreviated AAI_DSA-REQ) message transmitted to the base station by themobile station. The base station is then able to check the valueproposed by the mobile station or announce a substitute value, via anAAI_DSA-REQ message or an advanced air interface dynamic serviceaddition response (hereinafter abbreviated AAI_DSA-RSP) messagetransmitted by the base station.

In the following description, explained is a case that a mobile stationis explicitly or implicitly aware that a base station has successfullydecoded a bandwidth request indicator and a quick access messagetransmitted by the mobile station.

There can exist the following three cases. First of all, a mobilestation receives an ACK from a base station and then normally decodesthe received ACK. Secondly, a mobile station receives an ACK from a basestation and then fails to normally decode the received ACK. Thirdly, abase station may not transmit an ACK.

In case that a mobile station receives an ACK from a base station andthen normally decodes the received ACK, if a bandwidth request indicatortransmitted by the mobile station is included in the ACK and the ACKindicates that a quick access message was successfully decoded, themobile station can be explicitly aware that the base station hassuccessfully decoded the bandwidth request indicator and the quickaccess message, which had been transmitted by the mobile station.

In case that a mobile station receives an ACK from a base station andthen fails to normally decode the received ACK, the mobile station isunable to recognize whether a bandwidth request indicator transmitted bythe mobile station is included in the ACK. Therefore, the mobile stationimplicitly determines that the base station has successfully decoded thebandwidth request indicator and the quick access message, which had beentransmitted by the mobile station.

In case that a base station allocates an uplink resource to everybandwidth request indicator transmitted in a transmission opportunitybefore an ACK delay or normally receives bandwidth request indicatorsand quick access messages having been transmitted in the transmissionopportunity, the base station may not transmit an ACK for thecorresponding transmission opportunity. Therefore, the mobile stationimplicitly determines that the base station has successfully decoded thebandwidth request indicator and the quick access message, which had beentransmitted by the mobile station.

In case that the mobile station can be explicitly or implicitly awarethat the base station has successfully decoded the bandwidth indicatorand the quick access message, which has been transmitted by the mobilestation, it corresponds to one of the above-described three cases. Inparticular, the mobile station determines that the base station hassuccessfully decoded the bandwidth request indicator and the quickaccess message, which had been transmitted by the mobile station, unlessexplicitly receiving an ACK indicating that the bandwidth requestindicator or the quick access message, which had been transmitted by themobile station, was not received from the base station.

In case that a mobile station receives an ACK from a base station andthen normally decodes the received ACK, if a bandwidth request indicatortransmitted by the mobile station is included in the ACK and the ACKindicates that a quick access message was not successfully decoded, themobile station starts a timer having a default value previouslydetermined between the mobile station and the base station and thenswitches to a 5-step scheme.

In case that a mobile station receives an ACK from a base station andthen normally decodes the received ACK, if a bandwidth request indicatortransmitted by the mobile station is not included in the ACK, the mobilestation retries a random access.

After the mobile station has started the differentiated or defaultedtimer, if an uplink resource is allocated to the mobile station, themobile station stops the corresponding timer. If the uplink resource isnot allocated to the mobile station until the timer expires, the mobilestation retires a random access.

In the following description, explained is a case that a mobile stationtransmits a bandwidth request indicator to a base station only.

First of all, after a mobile station has transmitted a bandwidth requestindicator to a base station, if the mobile station explicitly orimplicitly becomes aware that the base station has successfully decodedthe bandwidth request indicator transmitted by the mobile station, themobile station starts a timer of a default value. If an uplink resourcefor a bandwidth request message transmission is allocated to the mobilestation, the mobile station stops the timer.

After a mobile station has sent a bandwidth request message to a basestation, a method of operating a timer is explained as follows.

First of all, if an uplink resource for a bandwidth request messagetransmission is allocated to a mobile station, the mobile station sendsa bandwidth request message via the allocated resource.

If the mobile station explicitly or implicitly becomes aware that thebase station has successfully decoded the bandwidth request message sentby the mobile station, the mobile station starts a differentiated timerdetermined according to a characteristic of data to transmit. If anuplink resource is allocated to the mobile station, the mobile stationstops the timer.

If the mobile station explicitly or implicitly becomes aware that thebase station has successfully decoded the bandwidth request message sentby the mobile station, it means a case that the mobile station does notreceive an ACK indicating that the base station fails to receive thebandwidth request message.

If the mobile station receives an ACK indicating that the base stationfails to receive the bandwidth request message from the base station,the mobile station retransmits a bandwidth request indicator or abandwidth request message.

In the following description, explained are operations of mobile andbase stations in a random access method according to a first embodimentof the present invention.

FIG. 28 is a diagram of a process for a mobile station to transmit abandwidth request indicator according to a first embodiment of thepresent invention.

Referring to FIG. 28, a mobile station waits for a transmissionopportunity, which amounts to the number selected by back-off algorithm,to transmit a bandwidth request indicator [S2810] and then transmits thebandwidth request indicator [S2820]. In doing so, in case of trying arandom access by a 3-step scheme, the mobile station transmits a quickaccess message together with the bandwidth request indicator.

Subsequently, the mobile station waits for an uplink resource allocation[S2830]. If a base station normally receives the bandwidth requestindicator only, the base station allocates an uplink resource for abandwidth request message transmission to the mobile station via a CDMAallocation advanced-MAP information element (CDMA allocation A-MAP IE).If the base station normally receives both of the bandwidth requestindicator and the quick access message, the base station allocates anuplink resource to the mobile station via an uplink (UL) basicassignment A-MAP IE.

FIG. 29 a is a diagram of a process for a mobile station to stand by foran uplink resource allocation according to a first embodiment of thepresent invention.

Referring to FIG. 29 a, a mobile station receives an ACK from a basestation in the course of waiting for an uplink resource allocation[S2901]. The mobile station checks the ACK to confirm whether abandwidth request indicator transmitted by the mobile station existswithin the ACK [S2902]. If the bandwidth request indicator transmittedby the mobile station is included in the ACK, the mobile station can beexplicitly or implicitly aware that the base station has successfullydecoded a quick access message transmitted by the mobile station. If so,the mobile station starts a differentiated timer [S2904]. Otherwise, themobile station starts a defaulted timer [S2905].

If the bandwidth request indicator transmitted by the mobile station isnot included in the ACK, the mobile station increments a retrial counterby ‘1’ [S2906]. If the retrial counter is set to be equal to a presetmaximum value, the mobile station ends a random access process [S2909].If the retrial counter is set to be smaller than a preset maximum value,the mobile station waits for a transmission opportunity to retry arandom access [S2908].

If the mobile station fails to receive the ACK at a timing point forreceiving the ACK, the mobile station implicitly determines that thebase station has successfully decoded both of the bandwidth requestindicator and the quick access message transmitted by the base station[S2917]. The mobile station then starts the differentiated timer[S2904].

Before the mobile station receives the ACK, if an uplink resource isallocated to the mobile station by the base station [S2910], the mobilestation checks whether the allocated resource is for the bandwidthrequest message transmission [S2911]. If the allocated resource is forthe bandwidth request message transmission, the mobile station transmitsthe bandwidth request message to the base station via the allocatedresource [S2912] and then starts the differentiated timer [S2913]. Indoing so, the differentiated timer is started after ACK/NACK for thebandwidth request message reception has been received from the basestation.

If the allocated resource is for the bandwidth request messagetransmission, the mobile station checks whether a size of the allocatedresource is suitable for a data transmission [S2914]. If it is able totransmit all data via the allocated resource, the mobile stationtransmits the data via the allocated resource [S2916]. If it is unableto transmit all data via the allocated resource, the mobile stationmakes a request for an additional uplink resource while transmitting thedata via the allocated resource [S2915] and then starts thedifferentiated timer [S2913]. In doing so, the differentiated timer isstarted after ACK/NACK for the data transmission has been received fromthe base station.

FIG. 29 b is a diagram of a process for a mobile station to stand by foran uplink resource allocation after having started a timer according toa first embodiment of the present invention.

After the mobile station has started the defaulted timer or thedifferentiated timer [S2905 or S2904, S2913], the timer may expirewithout the uplink resource allocation [S2920]. If so, the mobilestation increments the retrial counter by ‘1’ [S2921]. If the retrialcounter is set to be equal to a preset maximum value, the mobile stationends the random access process [S2925]. If the retrial counter is set tobe smaller than the preset maximum value, the mobile station waits for atransmission opportunity to retry the random access [S2924].

After the mobile station has started the defaulted timer or thedifferentiated timer [S2905 or S2904, S2913], if an uplink resource isallocated before the timer expires [S2926], the mobile station checkswhether the allocated resource is for the bandwidth request messagetransmission [S2927]. If the allocated resource is for the bandwidthrequest message transmission, the mobile station transmits the bandwidthrequest message to the base station via the allocated resource [S2928]and then starts the differentiated timer [S2929]. In doing so, thedifferentiated timer is started after ACK/NACK for the bandwidth requestmessage reception has been received from the base station. If an uplinkresource for the data transmission is allocated [S230], the mobilestation transmits the data [S2931].

If the allocated resource is for the bandwidth request messagetransmission, the mobile station checks whether a size of the allocatedresource is suitable for a data transmission [S2932]. If it is able totransmit all data via the allocated resource, the mobile stationtransmits the data via the allocated resource [S2934]. If it is unableto transmit all data via the allocated resource, the mobile stationmakes a request for an additional uplink resource while transmitting thedata via the allocated resource [S2933] and then starts thedifferentiated timer [S2929]. In doing so, the differentiated timer isstarted after ACK/NACK for the data transmission has been received fromthe base station.

FIG. 30 is a diagram of a process for receiving a bandwidth requestindicator in a base station according to a first embodiment of thepresent invention.

Referring to FIG. 30, a base station receives a bandwidth requestindicator [S3001]. The base station waits for a bandwidth requestindicator each transmission opportunity. If the base station normallydetects the bandwidth request indicator at the transmission opportunity,the base station performs another process according to whether a quickaccess message is normally received.

The mobile station transmits the bandwidth request indicator only or cantransmit both of the bandwidth request indicator and the quick accessmessage. If the mobile station transmits both of the bandwidth requestindicator and the quick access message, the base station may be able todecode the quick access message successfully or unsuccessfully.

If the base station receives the quick access message and thensuccessfully decodes the received quick access message, the base stationchecks whether there is an uplink resource amounting to a size requestedby the mobile station [S3003]. If there is the uplink resource, the basestation allocates the uplink resource to the mobile station [S3004].Otherwise, the base station stands by for an uplink resource [S3005].

If the mobile station does not transmit the quick access message or thebase station fails to successfully receive and decode the quick accessmessage, the base station checks whether an uplink resource for abandwidth request message transmission can be allocated to the mobilestation [S3006]. If there is the uplink resource, the base stationallocates the uplink resource to the mobile station [S3007] and thenwaits for the bandwidth request message [S3008]. Otherwise, the basestation stands by for an uplink resource [S3005].

FIG. 31 is a diagram of a process for a base station to re-obtainwhether a resource for allocation exists according to a first embodimentof the present invention.

Referring to FIG. 31, if an uplink resource to be allocated to a mobilestation exists before a subframe for transmitting an ACK, a base stationallocates an uplink resource for a data transmission to the mobilestation [S3103] or allocates an uplink resource for a bandwidth requestmessage transmission [S3104].

If an uplink resource to be allocated to a mobile station does not existbefore a subframe for transmitting an ACK, the base station transmits anAC to the mobile station in the subframe for transmitting the ACK[S3105] and then waits for an uplink resource to allocate to the mobilestation again.

FIG. 32 is a diagram for a base station to receive a bandwidth requestmessage according to a first embodiment of the present invention.

First of all, if a mobile station obtains an uplink resource enough tosend a bandwidth request message, the mobile station is able to sent thebandwidth request message or data except the bandwidth request message.

Referring to FIG. 32, a base station receives data [S3201] or receives abandwidth request message [S3202]. Having received the bandwidth requestmessage, the base station decodes the bandwidth request message [S3203].If the decoding is successful, the base station checks whether an uplinkresource amounting to a size requested by a mobile station can beallocated [S3204].

If the uplink resource exists, the base station allocates the uplinkresource to the mobile station [S3205]. Otherwise, the base stationwaits for an uplink resource [S3206].

If the base station fails to receive the bandwidth request message inthe resource allocated to the mobile station for a transmission of thebandwidth request message [S3209] or fails to decode the bandwidthrequest message, the base station checks whether an uplink resource forthe bandwidth request message transmission exists to be allocated to themobile station [S3208]. If the resource exits to be allocated, the basestation allocates the uplink resource for the bandwidth request messagetransmission [S3209]. In doing so, the base station informs the mobilestation that the bandwidth request message was not received or decodedsuccessfully.

A random access method according to a second embodiment of the presentinvention is explained as follows.

According to a second embodiment of the present invention, a mobilestation activates a timer at a timing point of sending a bandwidthrequest indicator or a bandwidth request message.

In the following description, explained is a case that a base stationsupports an ACK and that a mobile station transmits a bandwidth requestindicator and a quick access message to the base station.

First of all, a mobile station transmits a bandwidth request indicatorand a quick access message to a base station and then starts adifferentiated timer determined according to a characteristic of data totransmit.

Subsequently, if a code sent by the mobile station is included in an ACKreceived from the base station and if the mobile station is explicitlyor implicitly aware that the base station has successfully decoded thequick access message, the mobile station keeps operating the timer.

If a code sent by the mobile station is included in an ACK received fromthe base station and if it is indicated that the base station has failedin decoding of the quick access message, the mobile station stops thetimer and starts a defaulted timer.

If a code sent by the mobile station is not included in an ACK receivedfrom the base station, the mobile station stops the timer.

If an uplink resource is allocated, the mobile station stops the timer.

In the following description, explained is a case that a base stationsupports an ACK and that a mobile station transmits a bandwidth requestindicator to the base station.

First of all, a mobile station transmits a bandwidth request indicatorto a base station and then starts a timer having a default value. Inthis case, the default value can be previously defined in a manner ofbeing determined in consideration of a maximum scheduling delay forallocating an uplink resource for transmitting a bandwidth requestmessage. For instance, if frame information can be represented asmaximum 24 frames within CDMA Allocation A-MAP IE, it is able to definea default value set equal to or smaller than 24 frames. In this case,the default value can be defined in consideration of a time between atiming point of transmitting a bandwidth request indicator and a quickaccess message and a timing point of receiving an ACK.

If the mobile terminal can be explicitly or implicitly aware that thebase station has successfully received the bandwidth request message viathe ACK received from the base station, the mobile station keeps thetimer. Otherwise, the mobile station stops the timer.

If an uplink resource is allocated, the mobile station stops the timer.

In the following description, explained is a case that a base stationdoes not support an ACK and that a mobile station sends a bandwidthrequest message to the base station.

First of all, a mobile station transmits a bandwidth request message toa base station and then starts a differentiated timer determinedaccording to a characteristic of data to transmit.

If the base station announces that decoding of the bandwidth requestmessage sent by the mobile station was successful, the mobile stationkeeps operating the timer. If the base station announces that decodingof the bandwidth request message sent by the mobile station was notsuccessful, the mobile station stops the timer. Subsequently, the mobilestation retransmits the bandwidth request message or a bandwidth requestindicator according to a presence or non-presence of reallocation by thebase station.

If an uplink resource is allocated to the mobile station, the mobilestation stops the timer.

In the following description, explained is a case that a base stationdoes not support an ACK and that a mobile station transmits a bandwidthrequest indicator and a quick access message to the base station.

First of all, a mobile station transmits a bandwidth request indicatorand a quick access message to a base station and then starts adifferentiated timer determined according to a characteristic of data totransmit.

If the base station successfully decodes the bandwidth request indicatorreceived from the mobile station but fails the decoding of the quickaccess message, the base station allocates an uplink resource for abandwidth request message transmission within a default value or is ableto allocate an uplink resource for a bandwidth request messagetransmission within a minimum value of the differentiated timer values.

If the uplink resource for the bandwidth request message transmission isallocated to the mobile station, the mobile station stops the timer.

In case that the base station allocates the uplink resource for thebandwidth request message transmission within the default value, afterthe mobile station has transmitted the bandwidth request indicator andthe quick access message, if a value of the started differentiated timeris smaller than the default value, it may happen that the mobile stationretransmits the bandwidth request indicator.

FIG. 33 is a diagram for a case that a mobile station retransmits abandwidth request indicator.

Referring to FIG. 33, a mobile station transmits a first bandwidthrequest indicator and a quick access message [S3310] and then starts afirst differentiated timer. Yet, if the base station successfullyreceives and decodes the bandwidth request indicator but fails thedecoding of the quick access message, the base station allocates anuplink resource for a bandwidth request message transmission within adefault value.

If a value of the differentiated timer is smaller than the defaultvalue, the timer expires before an uplink resource is allocated to themobile station. Subsequently, the mobile terminal transmits a secondbandwidth request indicator and a quick access message to the basestation to retry a random access of the mobile station [S3320].

Subsequently, the base station receives the second bandwidth requestindicator and the quick access message and then successfully decodesthem. The base station allocates an uplink resource for the firstbandwidth request indicator [S3330]. If so, the mobile station stops thetimer and then sends a bandwidth request message [S3340]. The basestation then compares a flow ID of the bandwidth request message with aflow ID of the quick access message transmitted together with the secondbandwidth request indicator. If the flow IDs match each other, the basestation allocates an uplink resource having a size requested via thebandwidth request message [S3350]. In this case, after the mobilestation has transmitted the second bandwidth request indicator, the basestation allocates the uplink resource within the started timer.

Embodiments of the present invention can be implemented using variousmeans. For instance, embodiments of the present invention can beimplemented using hardware, firmware, software and/or any combinationsthereof.

In the implementation by hardware, a random access method according toone embodiment of the present invention can be implemented by at leastone selected from the group consisting of ASICs (application specificintegrated circuits), DSPs (digital signal processors), DSPDs (digitalsignal processing devices), PLDs (programmable logic devices), FPGAs(field programmable gate arrays), processor, controller,microcontroller, microprocessor and the like.

In case of the implementation by firmware or software, a methodaccording to each embodiment of the present invention can be implementedby modules, procedures, and/or functions for performing theabove-explained functions or operations. Software code is stored in amemory unit and is then drivable by a processor. The memory unit isprovided within or outside the processor to exchange data with theprocessor through the various means well-known to the public.

While the present invention has been described and illustrated hereinwith reference to the preferred embodiments thereof, it will be apparentto those skilled in the art that various modifications and variationscan be made therein without departing from the spirit and scope of theinvention. Thus, it is intended that the present invention covers themodifications and variations of this invention that come within thescope of the appended claims and their equivalents.

And, it is apparent that claims not in the explicitly cited relation canbe combined to configure a new embodiment or can be included as newclaims by correction after application.

Accordingly, the present invention provides the following effects oradvantages.

First of all, the present invention sets a resource allocation standbytime to differ according to a QoS level, thereby enhancing QoS.

Secondly, the present invention sets a resource allocation standby timeto differ according to a priority of a mobile station, thereby providinga service differentiated according to a mobile station priority.

Thirdly, a base station determines a location for transmitting ACK for arandom access code in a manner of informing a mobile station of an ACKdelay value in advance or using a predetermined ACK delay value, wherebyan overhead of ACK/NACK for the random access code can be minimized.

Fourthly, a mobile station uses a timer value determined according toACK/NACK of a base station in response to a bandwidth request indicator,quick access message or bandwidth request message transmitted by themobile station. Therefore, a timer is prevented from startingunnecessarily and a timer value suitable for a situation can be used.

1. A method for random access by a mobile station of a wireless communication system, the method comprising: transmitting a bandwidth request (BR) indicator and a quick access message; and starting a BR timer having a timer value determined according to a response to the transmission of the BR indicator and quick access message, wherein the BR timer is started with a fixed value previously determined if an acknowledgement is received indicating that decoding of the BR indicator is successful but decoding of the quick access message is unsuccessful.
 2. The method according to claim 1, further comprising stopping the BR timer if an uplink resource is allocated.
 3. The method according to claim 1, further comprising retransmitting the BR indicator and the quick access message if an uplink resource is not allocated to the mobile station before the BR timer expires.
 4. The method according to claim 1, further comprising: receiving a negative acknowledgement; and retransmitting the BR indicator and the quick access message.
 5. A method of random access by a mobile station in a wireless communication system, the method comprising: transmitting a bandwidth request (BR) indicator; receiving a response indicating successful reception of the BR indicator; starting a first BR timer according to the received response; and stopping the first BR timer if a first uplink resource for transmitting a BR header is allocated, wherein the BR header contains identifier information of the mobile station; transmitting the BR header by using the first uplink resource; starting a second BR timer after transmitting the BR header; and stopping the second BR timer if a second uplink resource for transmitting data is allocated.
 6. The method according to claim 5, wherein the first BR timer has a fixed value previously determined.
 7. The method according to claim 5, wherein the second BR timer has a differentiated value based on a service flow.
 8. The method according to claim 5, further comprising retransmitting the BR indicator if the second uplink resource is not allocated to the mobile station before the second BR timer expires. 